1. Field
The present invention concerns spectrally-based gamut mapping, namely, gamut mapping in a spectral color space.
2. Description of the Related Art
Color management systems are software-based systems that provide control over the color conversion of a color image from one device to another, such as from an image scanner or digital camera to a color printer or color monitor. One goal of color management is to retain good color fidelity when the color image is reproduced across a wide variety of different color devices, such that the reproduction of a color image will be perceived as a good match to the original color image even when reproduced on another device.
In a traditional color management system (CMS), color conversion is performed in a calorimetric color space, such as a CIEXYZ color space, or a color appearance space, such as a CIEJCh color space. Such color spaces are typified by their dimensionality, in that calorimetric and color appearance color spaces have three dimensions. Hereinafter, both calorimetric and color appearance color spaces will be referred to generically as “three dimensional color spaces”.
More recently, CMSs have been developed which work in spectral color spaces. Spectral color spaces are advantageous over calorimetric color spaces, in that spectral color spaces include far more information concerning the fundamental nature of the underlying color. Spectral color spaces are typified by high dimensionality. For example, a space of spectral reflectance has 31 dimensions, each corresponding to a different measurement of the physical stimuli's reflectance at each 10 mm interval in the visible light range of 400 to 700 nm. More compact forms of spectral color spaces have been proposed, and several researchers have proposed spectral color spaces with as few as six dimensions. Even at six dimensions, however, such dimensionality adds geometrically more complexity to the work performed by spectral CMSs as opposed to calorimetric CMSs.